Variable area nozzle



IN VEN TORS FREDERICK L. GEAR r Aprll 12, 1960 F. L. GEARY ET AL VARIABLE AREA NOZZLE Filed Oct. 25. 1952 WILL/AM GRANVILLE MYLOR JR.

VARIABLE AREA NOZZLE Frederick L. Geary, Springfield, Mass., and William G. Taylor, Jr., South Glastonbury, Conn., assignors to United Aircraft Corporation, East Hartford, Conn., a corporation of Delaware Application October 25, 1952, Serial No. 316,912

4 Claims. (Cl. 60-355) This invention relates to a propelling nozzle for a turbojet engine.

An object of this invention is to provide a propelling nozzle in which the flaps which control the efiective opening of the nozzle have a sliding movement.

Another object of this invention is to provide a nozzle which presents a substantially circular opening at its exit at any operating position.

. A further object of this invention is to minimize undesirable actuating loads on the flaps forming the nozzle.

Another object of this invention is to provide a nozzle which can be arranged so that closing loads are imposed thereon due to gas loads.

Other objects and advantages will become apparent from the following description.

In the accompanying drawings there is illustrated a suitable mechanical embodiment for the purpose of disclosing the invention. The drawings, however, are for the purpose of illustration only and are not to be taken .United States, P

as limiting or restricting the invention. It will be ap parent to those skilled in the art that various changes in the illustrated construction may be made without exceeding the scope of the invention.

Fig. l is a view in elevation of a jet engine and afterburner showing the relative position of the nozzle and also showing its operating cylinders.

Fig. 2 is an enlarged view partially in section of the rear portion of the afterburner shown in Fig. 1.

Fig. 3 is an end view looking in the direction of the arrows 3 of Fig. 2 showing the nozzle in a closed position. 7

Fig. 4 is a longitudinal sectional view on a larger scale taken through the nozzle showing part of the actuating mechanism.

Fig. 5 is a view taken along the line 5-5 of Fig. 4.

Fig. 1 shows a jet engine 2 having an air inlet 4, a compressor section 6, burner section 8, turbine section 10, and having an afterburner 12 and nozzle 14 attached thereto.

The afterburner 12 includes a diffuser section 16 and a burner section 18. Nozzle 14 is attached to the afterburner 12 and is actuated by pistons in cylinders 26 in a manner to be hereinafter described. As seen in Figs. 2, 4, and 5, the burner section 18 of the afterburner is constructed having two shells, an inner shell 28 and an outer shell, or shroud, 30. The specific construction of this afterburner does not form part of this invention and is shown and claimed in the copending application of Donald I. Jordan, Serial No. 316,905, filed October 25, 1952, now Patent No. 2,846,841, for a Pressurized Afterburner Cooling Shroud and the copending application of Edmund D. Brown, Serial No. 316,920, filed October 25,

1952, now Patent No. 2,846,842, for an Afterburner The space provided between the' Shroud Construction. end of inner shell 28 and the end of outer shell, or shroud, '30 is dimensioned so that'- when the nozzle 14 is open and the afterburner is on the two ends will be approxirnately just in meeting contact. An arrangement of this bers 34 used for any one nozzle.

forward set of bosses.

fi ce 2 type is shown and claimed in the copending application of Frederick L. Geary, Serial No. 284,789, filed April 28, 1952, for a Support Means, now Patent No. 2,735,262, dated February 21, 1956.

The nozzle 14 is comprised of two main parts, one part including those elements which remain fixed in relation to the engine and the other part including those elements which move in relation to the engine to place the nozzle in an open or a closed position.

The first, or fixed, part of the nozzle includes a ring member 32 which is attached to the afterburner by pairs of rib members 34 which extend longitudinally of the nozzle and are positioned substantially radially between the shell 30 and the ring 32. In the embodiment shown, as seen in Fig. 3, there are 12 pairs of these rib members 34. Also fixed to the afterburner (the shroud 30) is an annular member 36 of channel cross section. This annular member 36 is located rearwardly of rib members 34 and for a purpose to be hereinafter described.

The second, or movable, part of the nozzle includes a number of sliding flap members 38, each flap being reinforced by a center strengthening member 40. Each flap 38 is formed having a projected width at at its nozzle forming end and a projected width b at its other end which is connected to an actuating means and to the first, or fixed, partof the nozzle.

The projected width b is made a dimension which will fit between a pair of rib members 34. The number of flaps desired governs the number of pairs of rib mem- These two widths of the flap intersect at a line represented by point B along the flap. As can be seen from Fig. 4, this point in the closed position of the nozzle is located just forward of vsealing ring 42 which is located in annular member 36. Rib members 34 are sloped forwardly as at 44 to permit The other set of bosses 48 is located at the rearward part of the narrow width b and in line axially with the An axle 50 extends between each setof bosses 46 Each axle has a necked down portion 52 on each end which extends through a hole in its cm operating boss. Rollers 54 are rotatably mounted on the end of each necked down portion of an axle 50. Another axle extends between each set of bosses 48. Each of these axles has a necked down portion 56 on each end which extends through a hole in its cooperating boss.

Rollers 58 are rotatably mounted on the end of each necked down portion 56 of the axle mounted on bosses 48.

Each rib. member 34 has a pair of cam grooves located therein. These cam grooves, which are identical for each rib member 34, may be of various configurations to slide flaps 38 in any desired manner. However, in the modification shown in Figs. 2 and 4 the rearward cam groove 60 is formed along a straight line located approximately parallel to the extension of the end of the nozzle forming portion of the flaps 38.. As shown in Fig. 4,, this having its forward portion curved inwardly towards the axis of the afterburner. This arrangement provides for 3 movement of each nozzle flap in a straight line parallel to the rearward slot during the latter portion of the rearward movement of the fiaps and during the first portion of the forward movement. The angularity of these s'lots with respect to the axis of the afterburner thus causes a radial movement of each flap as an entirety as it is moved axially. For the distance of travel from the point on cam groove 62 at which the groove ceases to run parallelto cam groove 60 to the forward endsof the grooves the flaps are caused to pivot about the rearward rollers 58 as they are moved axially thereby moving the trailing edges of the fiaps away from the axis of the afterburner at a faster rate than during the portion of the flap movement where the slots are parallel. This action reduces the actuating reaction of the gases passing through the afterburner on the flaps of the nozzle.

Each roll'er'54 of each flap 38 is located in engagement with the forward cam grooves of its cooperating pair of rib members 34. Each roller 58 of each flap 38 .is located in engagement with the rearward cam grooves of its cooperating pair of rib members 34. As can be seen in Fig. 5, these rollers are of the pulley type where their sides prevent them from moving axially in the cam groove.

As seen in Fig. 3, each flap 38 is formed with its nozzle forming end having a bend 64 therein. This bend 64 extends from a point C at the rear of the flap on one side of center member 40 to a point D located at the forward end of the nozzle forming portion of flap 38. This bend 64 divides each flip into twoportions each having a different diameter, one poition66 on one side of said bend being of a larger diameter than the second portion 68' on the other side of the bend. The inner diameter of portion 66 is approximately the same as the outer diameter of portion 68. As the flaps slide into a closed position the portion 66 of each flap slides over the portion 68 of its adjacent flap. This provides a nozzle having a more nearly circular nozzle opening and also provides a good seal. While the flaps are shown constructed in this manner other means of overlapping. or cooperating may be used.

The forward portion of each flap 38 consisting of the -narrow width b has a bifurcated member 70 located on the outer side thereof. This member 70 is located at the forward end and in the center of the outer side of each flap. This member is attached to the actuating mechanism of said nozzle in a manner to be hereinafter described.

The actuating mechanism includes a hoop, or circular member, 72 which is located around the end of the afterburner and mounted for axial movement 'on tracks 74. A plurality of these tracks 74 are mounted around the afterburner. These tracks as shown are of the single rail type, being fixed to the afterburner. For each track '74 there is a bracket 76 located on the hoop on which there are mounted two pulley wheels 78. The bracket 76 includes two side plate members 80' which extend forwardly and radially inward from said hoop 72. A wheel 78 is rotatably mounted on each end of said bracket. These wheels support the hoop 72 on tracks 74 and permit axial movement.

Hoop 72 has mounted therearound a plurality of bifurcated brackets 82. An adjustable link 84 having a self-aligning bearing on each end extends between each bracket 82 on the hoop and the bifurcated member 70 of the flap which it actuat'es. The ball member of the Self-aligning bearing of one end of a link 84 is held between the bifurcated portions of bracket 82 by a clevis pin and the ball member of the self-aligning member of the other. end of the link is held between the bifurcated portions of the member 70 by a clevis pin.

Eachbracket 76 is attached to a piston in a cylinder 26 movement between the afterburner and cylinder. The piston rods 86, which actuate the flaps of the nozzle, are moved by connecting one end or the other of cylinder 26 to an operating pressure. While the operation of the nozzle can be performed manually, it is preferred that an automatic control be used. An automatic control of a type which could be used is shown and claimed in the application of 'Richard I. Coar, Serial No. 196,424, filed November 18, 1950, for a Control Device, now Patent No. 2,715,311, dated August 16, 1955. This control senses when the afterburner goes on or off, and opens or closes the nozzle accordingly and maintains it in that position. When the afterburner is on this nozzle actuator control 194 permits an actuating fluid to be directed by a conduit 262, manifold 116 and conduit sections 118 to the rearward ends of cylinders 26. This connection holds nozzle 14 in an open position. When the afterburner is off this nozzle actuator control 194 permits an actuating fluid to be directed by conduit 266, manifold 120 and conduit sections 122 to the forward ends ofcylin'ders 26. This connection holds nozzle 14 in a closed position. Conduit sections 118 and 122 are constructed of such a length and configuration that the cylinderscan pivot and not affect the function of these conduit sections.

Other specific nozzles are shown in application Serial No. 234,228, now Patent No. 2,815,643, dated December 10', 1957, application Serial No. 234,256, now Patent No. 2,813,395, dated November 19, 1957, application Serial No. 284,511, now Patent No. 2,770,944, dated November 20, 1956 and application Serial No. 316,911, now Patent No. 2,831,319, dated April 22, 1958.

We claim:

1. In combination, a duct, a nozzle having a plurality of overlapping flaps annularly arranged and adjustably supported in spaced relationship to said duct at all times, means for slidably mounting said flaps for axial movement', said mounting means having a plurality of ribs extending outwardly away from said duct, said ribs being mounted in pairs, one pair for each flap, each rib havingv two cam grooves therein said cam grooves extending radially and axially relative to said duct and having aft portions similarly inclined towards said duct, the cam grooves for each rib being axially spaced from each other, and each flap being located in part between the pair of ribs associated therewith and having a pair of axially spaced rollers mounted directly thereon for engagement with the cam grooves of a pair of ribs.

2. In combination, a duct, a nozzle for controlling the elfective area of the discharge end of the duct, said nozzle having a plurality of overlapping flaps annularly arranged and adjustably supported in spaced relationship to said duet at all times, means for mounting said fiapsfor axial sliding movement, said mounting means having a plurality of ribs extending outwardly away from said duct, said ribs being mounted in pairs, each rib having two axially spaced cam grooves therein, a rearward cam groove and a forward cam groove, .said rearward cam groove being substantially straight and inclined rearwardly towards the axis of the nozzle, said forward cam groove paralleling said rearward cam groove for part of its length then curving inwardly towards said duct, each flap being located in part between the pair of ribs associated therewith and ha ving a pair of axially spaced rollers thereon for engagement with the cam grooves of a pair of ribs said cam grooves causing a radial movement of the rearward ends of the flaps as the flaps move axially. 9

3. In combination, a duct, a nozzle for controlling the efiective area of the discharge end of the duct, said nozzle having-a plurality of overlapping flaps annularly arby piston rod 8 6. This rod is attached to bracket 76 ranged and adjustably supported in spaced relationship to said duct at all times, means for slidably mounting said flaps, said mounting means having a plurality of ribs extending outwardly away from said duct, said ribs 7 having two axially spaced cam grooves therein, each flap being located in part between the pair of ribs associated therewith and having a set of bosses mounted thereon for each cam groove, an axle located between each set of bosses with its ends projecting therethrough, a roller mounted on each end of each axle, each roller having engagement with its respective cam groove, one of said cam grooves being substantially straight and inclined to the axis of the nozzle, and the other of said grooves having an aft portion similarly inclined to the axis of said nozzle.

4. In combination, a duct, a nozzle for controlling the eifective area of the discharge end of the duct, said nozzle having a plurality of overlapping flaps annularly arranged and adjustably supported in spaced relationship to said duct at all times, means slidably mounting said flaps for axial movement, said mounting means having a plurality of ribs extending outwardly away from said duct, said ribs being mounted in pairs, each rib having two cam grooves therein, each flap being located in part between the pair of ribs associated therewith and having a set of bosses mounted thereon for each cam groove, an axle located between each set of bosses with its ends projecting therethrough, a roller mounted on each end of each axle, each roller having engagement with its respective cam, a bracket on said flap, actuating means connected to said bracket, the aft portions of the cam grooves being arranged at an angle similarly inclined to the duct to cause movement of the rearward ends of the flaps radially of the duct as the flaps are moved slidably in an axial direction.

References Cited inthe file of this patent UNITED STATES PATENTS 2,352,062 Zap June 20, 1944 2,502,315 Earhart Mar. 28, 1950 2,603,060 Brown July 15, 1952 2,603,062 Weiler et al. July 15, 1952 2,634,578 Kallal Apr. 14, 1953 2,637,163 Brown et al. May 5, 1953 2,693,078 Laucher Nov. 2, 1954 2,778,190 Bush Jan. 22, 1957 FOREIGN PATENTS v 506,714 Great Britain June 2, 1939 607,686 Great Britain Sept. 3, 1948 

